1. Field of the Invention
The present invention relates to a precise alignment method and a precise alignment apparatus for an optical component capable of shortening an alignment time in which an optical axis of a semiconductor laser device is highly precisely positioned to an optical waveguide provided in a component, and particularly, to a precise alignment method and a precise alignment apparatus for an optical component capable of shortening an alignment time in which an optical axis of a semiconductor laser device of a magnetic head manufacturing apparatus, attaching the semiconductor laser device to a slider of a magnetic head, is positioned to an optical waveguide provided in the slider.
2. Description of the Related Art
Generally, in a magnetic disk device, there has been a desire for high recording density with an increase in storage capacity. In recent years, as one of techniques of drastically improving the recording density, there has been proposed a heat-assisted magnetic recording technique in which a semiconductor laser beam is irradiated to a microscopic region of about several tens of nanometers by several tens of nanometers on a magnetic disk and a heat of 200° C. or higher and a magnetic field are applied thereto. A magnetic disk device that adopts the heat-assisted magnetic recording technique has a configuration in which an optical waveguide is opened to a desired position of a slider equipped with a magnetic head element so as to cause a laser beam to pass there through, a semiconductor laser device is highly precisely positioned to the optical waveguide, and the semiconductor laser device is fixed to the optical waveguide by a UV (UV light) curable resin or the like.
In the magnetic disk device that adopts the heat-assisted magnetic recording technique, there is a need to highly precisely position the semiconductor laser device to the optical waveguide opened to a desired position of the slider. However, since the slider is a microscopic component formed in, for example, a size in which a width is 0.7 mm, a depth is 0.85 mm, and a height is 0.23 mm, the semiconductor laser device is formed in a size in which a width is 0.2 mm, a depth is 0.1 mm, and a height is 0.5 mm and has a light emission point with a diameter of 1 and the optical waveguide opened to the slider has a diameter of 1 μm, the highly precise positioning operation may not be easily performed.
Regarding the related art of highly precisely positioning a semiconductor laser device to an optical waveguide opened to a desired position of a slider, a beam passing through the optical waveguide of the slider is captured by a near field pattern (NFP) camera while the slider moves in the X and Y directions with respect to the semiconductor laser device mounted on a sub-mount, X-axis and Y-axis coordinates of a slider position in which the intensity of the captured camera image becomes maximal are detected by an image process, and the semiconductor laser device is fixed to the slider position having a maximal intensity. Specifically, as illustrated in FIG. 4, the related art is used to highly precisely position an optical axis of a semiconductor laser device 01 supported by a sub-mount 40 and emitting a laser beam 90 to an optical waveguide 30 opened to a slider 26 for a magnetic disk device. Here, a NFP camera (not illustrated) captures the image of the slider 26 from the bottom surface thereof while the slider 26 moves in the X and Y directions in the state where the semiconductor laser device 01 emitting the laser beam 90 is fixed, the slider 26 is positioned based on the X-axis coordinate and the Y-axis coordinate of the slider 26 located at a position where the intensity of the captured image becomes maximal, the semiconductor laser device 01 moves downward to the optical waveguide 30 of the slider 26, and a UV curable resin between the slider 26 and the sub-mount 40 is irradiated with UV light so as to be cured, thereby aligning and fixing the semiconductor laser device and the optical waveguide to each other.
In the alignment technique of the related art, there is a limitation in the frame rate (the number of frames captured for one second) of the NFP camera for capturing an image, and the moving speed at which the slider moves in the X and Y directions with respect to the semiconductor laser device may not be a high speed in order to perform a highly precise positioning operation. For this reason, the alignment operation is performed for a long time, and hence a problem arises in that the magnetic head manufacturing time redundantly increases.
Furthermore, Patent Document below may be given as a cited document of the related art of highly precisely positioning the semiconductor laser device to the optical waveguide opened to a desired position of the slider. JP 2013-217999 A discloses a precise alignment technique for an optical component that prevents an erroneous positioning operation of a slider due to stray light by performing a step of scanning a plurality of frame images including a laser beam passing through an optical waveguide of the slider while relatively moving a predetermined region of the slider and a laser device emitting a laser beam in a zigzag shape in the X and Y directions when the laser beam emitted from the laser device is aligned to the slider having the optical waveguide opened thereto, a step of extracting a frame image f0 of maximal illuminance including an optical image subjected to a circularity filter from the plurality of captured frame images, and a step of extracting X-axis and Y-axis coordinates of an optical image having a maximal intensity and subjected to a circularity degree checking process for XY peripheral frame images separated by ± three frames in the X and Y directions with respect to the X-axis and Y-axis coordinates of the frame image f0.